The single-layer graphene film, when incorporated with molecular-sized pores, is predicted to be the ultimate membrane. However, the major bottlenecks have been the crack-free transfer of large-area graphene on a porous support, and the incorporation of molecular-sized nanopores. Herein, we report a nanoporous-carbon-assisted transfer technique, yielding a relatively large area (1 mm2), crack-free, suspended graphene film. Gas-sieving (H2/CH4 selectivity up to 25) is observed from the intrinsic defects generated during the chemical-vapor deposition of graphene. Despite the ultralow porosity of 0.025%, an attractive H2 permeance (up to 4.1 × 10−7 mol m−2 s−1 Pa−1) is observed. Finally, we report ozone functionalization-based etching and pore-modification chemistry to etch hydrogen-selective pores, and to shrink the pore-size, improving H2 permeance (up to 300%) and H2/CH4 selectivity (up to 150%). Overall, the scalable transfer, etching, and functionalization methods developed herein are expected to bring nanoporous graphene membranes a step closer to reality.
展开▼
机译：当单层石墨烯膜结合分子大小的孔时，被认为是最终的膜。然而，主要的瓶颈是大面积石墨烯在多孔载体上的无裂纹转移，以及分子大小的纳米孔的结合。本文中，我们报道了一种纳米孔碳辅助转移技术，可产生相对较大的面积（1 mm 2 ），无裂纹的悬浮石墨烯薄膜。从石墨烯化学气相沉积过程中产生的固有缺陷观察到了气体筛分（H2 / CH4选择性高达25）。尽管有0.025％的超低孔隙率，但H2的渗透率仍然很有吸引力（高达4.1×10 −7 mol m −2 s −1 Pa < sup> -1 ）。最后，我们报告了基于臭氧功能化的蚀刻和孔修饰化学方法，用于蚀刻氢选择性孔，并缩小孔径，从而提高H2渗透率（最高300％）和H2 / CH4选择性（最高150％）。总体而言，本文开发的可扩展的转移，蚀刻和功能化方法有望使纳米多孔石墨烯膜更接近现实。
展开▼
